Combination Switch Reading Function

WARNING: This page is about a different car, the 2012 Nissan Pathfinder. However, it is still accessible from the selected car via links, so may be relevant.

Description

BCM reads the status of the combination switch at 10 ms intervals normally.

Fig 1: Combination Switch Input And Output Patterns
Courtesy of NISSAN NORTH AMERICA, INC.

NOTE: BCM reads the status of the combination switch at 60 ms intervals when BCM is controlled at low power consumption control mode.
BCM operates as follows and judges the status of the combination switch.

It operates the transistor on OUTPUT side in the following order: OUTPUT 1 → 2 → 3 → 4 → 5, and outputs voltage waveform.
The voltage waveform of OUTPUT corresponding to the formed circuit is input into the interface on INPUT side if any (1 or more) switches are ON.
It reads this change of the voltage as the status signal of the combination switch.

Fig 2: BCM Output And Input Voltage Waveform
Courtesy of NISSAN NORTH AMERICA, INC.

Operation Example

In the following operation example, the combination of the status signals of the combination switch is replaced as follows: INPUT 1 - 5 to "1 - 5" and OUTPUT 1 - 5 to "A - E".

Example 1: When a switch (TAIL LAMP) is turned ON

The circuit between OUTPUT 4 and INPUT 5 is formed when the TAIL LAMP switch is turned ON.

Fig 3: Combination Switch Circuit Diagram Example (Tail Lamp ON)
Courtesy of NISSAN NORTH AMERICA, INC.
BCM detects the combination switch status signal "5D" when the signal of OUTPUT 4 is input to INPUT 5.
BCM judges that the TAIL LAMP switch is ON when the signal "5D" is detected.

Example 2: When some switches (TURN RH, TAIL LAMP) are turned ON

The circuits between OUTPUT 1 and INPUT 5 and between OUTPUT 4 and INPUT 5 are formed when the TURN RH switch and TAIL LAMP switch are turned ON.

Fig 4: Combination Switch Circuit Diagram Example (Turn RH, Tail Lamp ON)
Courtesy of NISSAN NORTH AMERICA, INC.
BCM detects the combination switch status signal "5AD" when the signals of OUTPUT 1 and OUTPUT 4 are input to INPUT 5.
BCM judges that the TURN RH switch and TAIL LAMP switch are ON when the signal "5AD" is detected.